Date: Tue, 11 Dec 2007 09:54:37 -0600 From: Josh Paetzel <josh@tcbug.org> To: freebsd-questions@freebsd.org Cc: Javier =?iso-8859-1?q?Mart=EDn?= Rueda <jmrueda@diatel.upm.es>, Valerio Daelli <valerio.daelli@gmail.com> Subject: Re: fsck of big disk Message-ID: <200712110954.40662.josh@tcbug.org> In-Reply-To: <27dbfc8c0712110719u74e783a1t9156145badb739c6@mail.gmail.com> References: <27dbfc8c0712060134u3580b5b0v24a7bc3301c05692@mail.gmail.com> <475E97E9.5060504@diatel.upm.es> <27dbfc8c0712110719u74e783a1t9156145badb739c6@mail.gmail.com>
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--nextPart2415618.IUyeoQ24c3 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Tuesday 11 December 2007 09:19:46 am Valerio Daelli wrote: > Hi, > thanks a lot for your answer. > > > > we have a freshly installed FreeBSD 6.2 machine with a gstriped > > > external disk, of 5.3Tb. The disk is composed of two slices of 2.6 Tb. > > > We are trying to have a (background) fsck of it but few hours later > > > since the start of the check > > > the host get unresponsive: it responds to ping but it doesn't let > > > login anyone, nor by ssh > > > nor by console. > > > > What do you get if you press Control-T on the console when it is > > unresponsive? > > We are not able to login via console nor via ssh. > Pheraps you suggest me to press Control-T on the console even if I am not > logged on. I did not try, sorry. > > > When you do a background fsck there is a point at which a snapshot of > > the filesystem is taken, although I'd say that happens at the beginning > > of the check. The problem is that with 5.3 Tb, it may take quite a while > > to take the snapshot, and during that time the system blocks any process > > that tries to write to the filesystem. Maybe that's what you are > > experiencing. > > What you explained us sounds very interesting. But anyway we simply > solved by disabling background fsck on such a big partition. We had > panics and reboot > and we did not want to risk on a production host. > Bye > > Valerio Daelli What you are probably running in to is memory starvation. In my experience= =20 fsck on a moderately filled disk uses something on the order of 1 gig of RA= M=20 per TB of filesystem. If you have this in an array with less than 4 gigs o= f=20 RAM it's possible that it was just buried in swap and spending all it's tim= e=20 moving pages in and out as opposed to doing anything useful. =2D-=20 Thanks, Josh Paetzel PGP: 8A48 EF36 5E9F 4EDA 5A8C 11B4 26F9 01F1 27AF AECB --nextPart2415618.IUyeoQ24c3 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQBHXrLAJvkB8SevrssRAlhKAJsFjihnF1T1WWqS21WC9t8Qfb1v4gCfQ9G4 ct+izY7Etwzmhuva717LEPg= =CiZX -----END PGP SIGNATURE----- --nextPart2415618.IUyeoQ24c3--
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